All-optical nonlinear control of circularly polarized light in birefringent fibers

Polarization state manipulation and tunability are two highly desirable objectives of utmost importance for the development of many applications, especially in optical fiber-based systems. In this article, we present in detail a comprehensive theory for describing and controlling the nonlinear polarization conversion of circularly polarized light in birefringent optical fibers (BOFs). We use our theory to provide a nonlinear model that allows obtaining the accurate input powers with which we can tune the most common continuous-wave polarization states at the BOF output. To analyze the polarization instability of the output optical signals, we define a parameter that gives a magnitude of the polarization instability as a function of the input power. The analytical results we provide agree accurately with the results obtained through numerical techniques. Our theory opens up new perspectives and provides considerable physical insight on the all-optical polarization control with BOFs.